The service desk is not a process byt a function: Mainly to provide a single point of contact between the business and IT. I like to think of the Service Desk as the Public Face of IT to the business - which means it is the Public Face of everything IT does, and not just Incident Management. There isn't a process 'conflict' the way there would be betwee Incident and Problem management.

The Service Desk is where Incidents are raised and recorded. (It would be difficult to imagine how single point of contact would be achieved if there was somewhere else end-users and customers could go to report incidents.)

At some point in the incident life-cylce responsibility for resoultion activity may be handed to parties not on the service desk. They may need to seek addintional info from the source of the incident - who ever raised in from the business.

It depends on the nature of the organistation and the skills of the people working the incident - but in some cases you may want strong re-inforcement of the single point of contact objective and require all communication be through the Service Desk staff. Or, as is more likely, you will allow support staff to interact with end-users and customers where they need to - as this will entail less double-handling, and attenuate the chinese-whispers effect of information being passed form person to person.

The case for incident closure at the Service Desk is stronger. Closure should always be negotiated with the client who raised the incident. Service desk staff are trained to think in terms of services and business capability, and are better palced to help a client apply a work around (remember the underlying problem is not always fixed at resolution). Without adequate training in the business, technical staff may not be well placed to negotiate closure.

Giving the Service Desk responsibility for closure is simply acknowledging the role they can play within Incident Management - it is not a confusion of two distinct processes.

You should always consider what the Service Desk can contribute to all the processes - after all they are closest to the business, and have day-to-day, on-the-graound knowledge that can easily be missed at othe levels of process management.